Carton end wall structure

ABSTRACT

In a folding carton formed of foldable paperboard, an end wall structure including, an inner flap, a pair of intermediate flaps having interlocking engagement with the inner flap, an outer flap having sealing engagement with said inner and intermediate flaps, and means whereby the inner flap and portions of the intermediate flaps present generally co-planar surfaces engaging the outer flap.

United States Patent [191 Muth ( 1 Apr. 10, 1973 CARTON END WALL STRUCTURE [75] Inventor: Richard J. Muth, Kent, Wash.

[73] Assignee: Container Corporation of America,

Chicago, Ill.

[22] Filed: Apr. 13, 1971 [21] Appl.No.: 133,503

[52] US. Cl ..229/36 [51] Int. Cl. ..B65d 5/26 [58] Field of Search ..229/36, 35

[56] References Cited UNITED STATES PATENTS 1,554,099 9/1925 Kolbe ..229/ 35 3,285,143 11/1966 Baker ..229/35 X 3,285,494 I l/l966 Baker ..229/36 2,829,817 4/1958 Halpcm 3,086,691 4/1963 Fobiano ..229/ 35 Primary Examiner-Davis T. Moorhead Attorney-Carpenter, Ostis & Lindberg [57] ABSTRACT In a folding carton formed of foldable paperboard, an end wall structure including, an inner flap, a pair of intermediate flaps having interlocking engagement with the inner flap, an outer flap having sealing engagement with said inner and intermediate flaps, and

means whereby the inner flap and portions of the intermediate flaps present generally co-planar surfaces engaging the outer flap.

1 Claim, 6 Drawing Figures PAIENTED APR 1 01ers FIG] 28 R as. 26

36a 26&

2O H66 ii 7 INVENTOR F164 4 m I ATTORNEYS RICHARD J. MUTH CARTON END WALL STRUCTURE One of the problems incurred in forming a seal-end carton wherein certain of the overlapping end flaps have interlocking as well as sealing engagement with each other is that if the co-engaging surfaces are not generally co-planar, a good sealing bond is difiicult to achieve.

It is therefore an object of this invention to provide, in a seal-end carton with interlocking end flaps an improved method of increasing the amount of surface contact between engaging flap portions to be sealed.

A more specific object of the invention is the provision, in a carton of the type described, of raised and depressed portions on interlocking flaps which cooperate to provide generally co-planar surfaces for engagement with a related flap.

These and other objects of the invention will be apparent froman examination of the following description and drawings, wherein:

FIG. 1 is a plan view of a folding carton blank from which the carton of the other views may be formed;

FIG. 2 is a perspective view of a carton embodying features of the invention, as seen in a partially erected condition;

FIG. 3 is an end view of the structure illustrated in FIG. 2 with the end walls shown in completely erected condition;

FIG. 4 is a fragmentary vertical section taken on line 4-4 of FIG. 3;

FIG. 5 is a fragmentary end view of the structure illustrated in the previous views but with the intermediate flap shown in the position prior to being interlocked with the inner end flap; and

FIG. 6 is a view similar to FIG. 5 but illustrating a slightly modified form of the invention.

It will be understood that, for purposes of clarity, certain elements have been intentionally omitted from certain views where they are believed to be illustrated to better advantage in other views.

Referring now to the drawing for a better understanding of the invention, and particularly to FIGS. 1 and 2, it will be seen that the carton may be formed from a unitary blank, indicated generally at B of foldaflaps 22 is provided with locking car 26 adapted to be received within a related locking slit 28 cut in inner end flap 20.

As best seen in FIG. 2, intermediate flaps 22 are folded at right angles to their panels from which they are attached, so as to overlap outer marginal portions of inner end flap 20, with their locking ears 26 received within inner end flap locking slits 28. As best seen in FIGS. 1 and 2, each inner end flap 20 is provided with a pair of crease scores 30 which extend from points on fold line 21 to the lower end of a related locking slit 28. As best seen in FIGS. 2 and 4, the effect of the crease scores 30 is to provide a central raised area 32, lying in the area defined by the crease scores and fold line 21, and also a pair of side areas 34, which lie above the crease scores 30 and are depressed with respect to the central area.

Thus, it will be seen that when the intermediate end flaps 22 are folded in position to interlock within the slits 28 of the inner end flap they lie within the side areas with the lower edges 36 of flaps 22 in abutting relation with the edges or shoulders 38 provided by the crease scores 30. Thus, the outer surfaces of the intermediate end flaps 22 are co-planar with the outer surface central area 32 of the inner end flap to provide more complete full face engagement with the inner surface of the outer end flap 24 when it is folded over and bonded thereto either by a heat scalable coating or in some other type of adhesive bond. This is best illustrated in FIG. 4.

Because of the co-planar relationship between the outer surfaces of the inner and intermediate end flaps and the inner surface of the outer end flap it is possible to obtain more complete and uniform bonding throughout the entire cross-section of the end wall and thereby provide a more perfect seal for the carton end.

FIG. 5 illustrates the preferred contour for the lower edges of end wall intermediate flaps 22, however, where desired a slightly different contour may be provided as shown by the line 36a in FIG. 6 of the drawing.

I claim:

1. In a folding carton formed from a unitary blank of paperboard having foldably interconnected opposed ble paperboard cut and scored to provide aplurality of airs of major and minor panels forming a tubular hingedly interconnected panels which form a tubular structure with end flaps arranged in overlapping relationship to form a closure for the ends of the carton.

As seen in FIG. 1, the main portion of the carton blank includes an inner front wall panel 10, a bottom wall panel 12, a rear wall panel 14, an upper wall panel 16, and an outer front wall panel 18 which are hingedly attached to each along parallel fold lines ll, l3, l5, and 17, respectively. When end panels of the blank are joined, with the front wall inner and outer panels 10 and 18 secured to each other in overlapped relation to form a common front wall, there is provided a tubular structure, each end of which is closed by a plurality of end flaps folded into overlapped relation and interlockingly sealingly connected to each other.

Each end wall includes an inner end flap 20 hingedly attached along fold line 21 to an end edge of bottom wall panel 12, a pair of intermediate flaps 22 hingedly attached along fold lines 23 to front wall inner panel 10 and rear wall panel 14, and an outer end flap 24 hingedly attached along fold line 25 to upper wall panel 16. It will be seen that each of the intermediate end structure, a closure arrangement for an end of said structure comprising:

a. an inner end flap hingedly attached to one of said major panels along a fold line and having:

i. a pair of locking slits spaced inwardly from opposed free side edges of said inner end flap and each extending from a first point spaced inwardly from said fold line to a second point spaced inwardly from the free edge opposite said fold line;

ii. a crease score defining a shoulder extending from the first point 'of each slit at an angle to said fold line to a point inwardly adjacent a related one of said opposed free side edges of said inner end flap;

iii. said crease scores and said shoulders and said fold line defining therebetween a central area of said inner end flap which is raised with respect to the remaining side areas of said inner end p;

b. a pair of intermediate end flaps hingedly attached to said minor panels and each having:

i. a locking ear adapted to enter a related slit of said inner end flap and to move into locking engagement therewith;

ii. an edge on said intermediate end flap coextensive with a related crease score and movable into abutting relationship with the related shoulder of said crease score upon locking engagement with said locking slit;

c. said intermediate end flaps when in such locked lo 

1. In a folding carton formed from a unitary blank of paperboard having foldably interconnected opposed pairs of major and minor panels forming a tubular structure, a closure arrangement for an end of said structure comprising: a. an inner end flap hingedly attached to one of said major panels along a fold line and having: i. a pair of locking slits spaced inwardly from opposed free side edges of said inner end flap and each extending from a first point spaced inwardly from said fold line to a second point spaced inwardly from the free edge opposite said fold line; ii. a crease score defining a shoulder extending from the first point of each slit at an angle to said fold line to a point inwardly adjacent a related one of said opposed free side edges of said inner end flap; iii. said crease scores and said shoulders and said fold line defining therebetween a central area of said inner end flap which is raised with respect to the remaining side areas of said inner end flap; b. a pair of intermediate end flaps hingedly attached to said minor panels and each having: i. a locking ear adapted to enter a related slit of said inner end flap and to move into locking engagement therewith; ii. an edge on said intermediate end flap coextensive with a related crease score and movable into abutting relationship with the related shoulder of said crease score upon locking engagement with said locking slit; c. said intermediate end flaps when in such locked position lying upon said side areas of said inner end flap and being coplanar with said central area; d. an outer end flap hingedly attached to the other of said major panels and foldable into overlapping sealing engagement with portions oF said intermediate flaps and said central area of said inner end flap. 